The present invention relates to a device for the transfer of substances between two fluids while simultaneously tempering at least one of the two fluids by means of a third fluid, and more particularly, the present invention is mainly intended for use as a so-called blood oxygenator for mixing oxygen or oxygen containing gas into the blood of a patient before returning the blood to the patient.
Prior art blood oxygenators are known in which a patient's blood passes along one side of a semipermeable membrane with an oxygen containing gas passing on the other side thereof so that oxygen bubbles diffuse through the membrane into the blood to achieve an effective oxygenation thereof. In such prior art blood oxygenators, it is also known to temper at least one of the fluids being conducted along one side of the semipermeable membrane. For example, in U.S. Pat. Nos. 3,212,498 and 3,332,746, there are disclosed blood oxygenator apparatus in which blood is conducted between pairs of semipermeable membranes with oxygen and/or dialysis solution arranged to be conducted on the outer surfaces of the semipermeable membrane to result in diffusion of the second fluid into the blood. In each of these apparatus, frame members or apparatus are provided between which the pairs of membranes containing blood are supported and between which flow paths for oxygen and/or dialysis fluid are defined for diffusion of substances through the membranes. The frame apparatus also includes means for tempering of one of the fluids being used in the diffusion process. This tempering in these prior art arrangements has comprised passing a third fluid along one side of a plate member of the frame apparatus with one of the other fluids passing along the other side of the plate member. That is, in each of these prior art references, the tempering fluid is passed along one side of a plate and the oxygen containing fluid or dialysis fluid passed along the opposing side of the plate so that the oxygen containing fluid or dialysis fluid is tempered.